CVE-2025-37932: Linux kernel · sch_htb: make htb_qlen_notify() idempotent
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 4.4.0-1145.151 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 14% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.4.0-1145.151, 4.15.0-1190.205~14.04.1, 4.4.0-270.304~14.04.1 +113
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 20 May 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7607-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7607-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7608-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7608-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7608-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7609-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7609-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7610-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7611-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7608-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7609-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7618-1 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: sch_htb: make htb_qlen_notify() idempotent htb_qlen_notify() always deactivates the HTB class and in fact could trigger a warning if it is already deactivated. Therefore, it is not idempotent and not friendly to its callers, like fq_codel_dequeue(). Let's make it idempotent to ease qdisc_tree_reduce_backlog() callers' life.
References
- ubuntu.com/security/CVE-2025-37932 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-37932 (opens in a new tab)
- git.kernel.org/linus/5ba8b837b522d7051ef81bacf3d95383ff8edce5 (opens in a new tab)
- git.kernel.org/stable/c/0a188c0e197383683fd093ab1ea6ce9a5869a6ea (opens in a new tab)
- git.kernel.org/stable/c/5ba8b837b522d7051ef81bacf3d95383ff8edce5 (opens in a new tab)
- git.kernel.org/stable/c/73cf6af13153d62f9b76eff422eea79dbc70f15e (opens in a new tab)
- git.kernel.org/stable/c/a61f1b5921761fbaf166231418bc1db301e5bf59 (opens in a new tab)
- git.kernel.org/stable/c/bbbf5e0f87078b715e7a665d662a2c0e77f044ae (opens in a new tab)
- ubuntu.com/security/notices/USN-7607-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7607-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7608-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7608-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7608-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7609-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7609-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7610-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7611-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7608-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7609-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7618-1 (opens in a new tab)